1. Field of the Invention
The invention relates to a data display device including a light-guide element made of an optically transparent material having at least two polished surfaces faced to one another, whereby at least one surface contains at least one gravure forming a diffuse-reflective character, and a light source arranged close to the light-guide element to illuminate said character.
2. Description of the Prior Art
This invention is in the class of illumination engineering as well as in the class of advertising-information technologies. The claimed device may find its application in architecture as interior lamps doubling for functions of decorative luminaries.
The principle of action of the claimed device is based on well-known laws of geometric optics. Among these laws are:    1) the law of conductivity of light beams in an optically transparent media having a refractive index n1>1.0, these media being in contact with-another medium having a refractive index n2, with n1>n2, for example, air (n2=1.0);    2) the law of diffuse reflection of light beams from local deformations of polished surfaces.
Due to the condition n1>n2 and owing to the polished reflecting surface, light beams do not escape the light-guide media if the condition of a limit angle of complete internal reflection is met (N. S. Kapany. Fiber Optics. Principles and Applications. Academic Press. N.Y. 1967).
What makes the claimed device the issue of the day is a new field of its application different from advertising-information purposes, by virtue of a fuller use of potentialities inherent in light-guide properties of optically transparent materials.
In advertising-information technologies, an extensive use is made of information screens called “Acryllights” produced by many advertising companies. All known “Acryllights” are made according to a uniform design of a device which comprises a light-guide element made of an optically transparent material having polished flat surfaces in the form of a light-guide plate (of a laminar rectangular shape), one of the surfaces being furnished with a set of engraved characters illuminated laterally through a polished surface by means of a light source. A principal drawback of the known device lies in its structural imperfection as dictated by a traditional approach to an information screen thought of as a plane. Such an approach comes into an apparent conflict with laws of light conductivity. These laws endow a light-guide element with “freedom of choosing any shape other than a rectilinear one” providing that the condition n1>n2 and the condition of full internal reflection are met. Another drawback of the device known from the art is associated with the use of luminescent light sources in “Acryllights”, above all in the form of tubes that are matched in length to the size of the light-guide plate. Diameters of the tube luminescent light sources exceed the thickness of the light-guide element, so the effectiveness of the lighting of diffuse-reflecting characters is low. Also, the size of luminescent light sources prevents some light-guide elements from being used in one unit.
The object of the invention is to procure a device for displaying data with enhanced visualization possibilities in respect to a data display device known in the art.